In many fuel supply systems applicable to internal combustion engines, fuel injectors are used to inject fuel pulses into the engine combustion chamber. A commonly used injector is a closed-nozzle injector which includes a nozzle assembly having a spring-biased nozzle valve element positioned adjacent the nozzle orifice for allowing fuel to be injected into the cylinder. The nozzle valve element also functions to provide a deliberate, abrupt end to fuel injection, thereby preventing a secondary injection which causes unburned hydrocarbons in the exhaust. The nozzle valve is positioned in a nozzle cavity and biased by a nozzle spring so that when an actuated force exceeds the biasing force of the nozzle spring, the nozzle valve element moves to allow fuel to pass through the nozzle orifices, thus marking the beginning of the injection event.